Major Ahmed, of the ERD's 1st Brigade, said the some Federal Police units tasked with holding ground captured by the ERD overnight have been withdrawing and ceding newly fought territory to the Islamic State group.

"My men are dying for these streets and they [the Federal Police] are just giving it away."

The Rapid Response Division, which numbers around 3,500, has seen its role grow exponentially as fighting has moved into the city's west, and as the ICTS have taken on a more supportive role in the operation.

Though the fall of IS in Mosul is a forgone conclusion in the eyes of many, Lieutenant Colonel Abdel Amir al-Mohammedawi warned against too urgent an assault on the old city, where narrow streets, dark alleys and tight corners make it difficult for large armoured vehicles to progress, forcing foot patrols to risk deadly encounters against insurgent fighters in the casbah, much of which is believed to be rigged with improvised explosive devices.

"We favour a slow and careful fight in the old city; we don't want our men to get hurt," Mohammedawi told The New Arab.

"We could take it in a week, if we wanted to, but we would take a lot of casualties and cause much damage to the Old City."

The Old City is the most densely populated part of Mosul.

As many as 400,000 civilians are believed trapped here. At the city's heart is the Grand Mosque of Al-Nuri, where Abu Bakr Al-Baghdadi declared the caliphate in 2014.

Its capture will serve as a huge symbolic defeat for the Islamic State group.

The blaze has finally been put out following months of dangerous firefighting carried out by specialist teams from Baghdad [Anadolu]

South of Mosul, in the town of Qayarrah, which was recaptured from IS in August, the last of 19 oil wells set alight by IS militants as they retreated from the town was extinguished on Tuesday.

The Ministry of Oil announced that the blaze, billowing thick black clouds which became a hallmark of IS' toxic legacy, had finally been put out after months of dangerous firefighting carried out by specialist teams from Baghdad.

The wells had been burning for close to nine months, costing the local economy millions in potential oil revenue and leaving a poisonous darkness looming over the town long after its liberation from the Islamic State group.

Gareth Browne is reporting from the front lines of the fight to retake Mosul from the Islamic State group. Follow him on Twitter: @BrowneGareth